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251934-YTG-G-0708
Johnson Controls Unitary Products 67
Altitude/Temperature Correction Factors
Air
Temp.
Altitude (Ft.)
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
40 1.060 1.022 0.986 0.950 0.916 0.882 0.849 0.818 0.788 0.758 0.729
50 1.039 1.002 0.966 0.931 0.898 0.864 0.832 0.802 0.772 0.743 0.715
60 1.019 0.982 0.948 0.913 0.880 0.848 0.816 0.787 0.757 0.729 0.701
70 1.000 0.964 0.930 0.896 0.864 0.832 0.801 0.772 0.743 0.715 0.688
80 0.982 0.947 0.913 0.880 0.848 0.817 0.787 0.758 0.730 0.702 0.676
90 0.964 0.929 0.897 0.864 0.833 0.802 0.772 0.744 0.716 0.689 0.663
100 0.946 0.912 0.880 0.848 0.817 0.787 0.758 0.730 0.703 0.676 0.651
Gas Heat Minimum Supply Air
Size
(Tons)
Heat Size
Supply Air (CFM)
Cooling Heating
Min Max Min Max
180
(15)
24 4500 7000 4500 7000
32 4500 7000 4500 7000
210
(17.5)
24 6000 8750 6000 8750
32 6000 8750 6000 8750
240
(20)
24 6000 9400 6000 9400
32 6000 9400 6000 9400
300
(25)
24 7500 12500 7500 12500
32 7500 12500 7500 12500
0.600
0.650
0.700
0.750
0.800
0.850
0.900
0.950
1.000
1.050
1.100
40 50 60 70 80 90 100
Air Temperature (ºF)
Correction Factor
Sea Level
1000 ft
2000 ft
3000 ft
4000 ft
6000 ft
7000 ft
8000 ft
9000 ft
10000 ft
5000 ft
For units with VFD and gas heat, the speed of the indoor
blower motor continues to be controlled by duct static
pressure via the VAV control board.
If there are VAV boxes present in the duct system,
the boxes must be driven to the full-open position
using a customer-supplied power source to assure
adequate airflow across electric heating elements
or gas heat exchanger tubes.